Vulpes velox: Moehrenschlager, A., Sovada, M. & Members of the IUCN SSC Canid Specialist Group - North America Regional Section

The Swift Fox (Vulpes velox) was once common in the shortgrass and mixed-grass prairies of the Great Plains of North America. The species' abundance declined and its distribution retracted following European settlement of the plains. By the late 1800s, the species had been largely extirpated from the northern portion of its historical range, and its populations were acutely depleted elsewhere. Swift Fox populations have naturally recovered somewhat since the 1950s, but overall abundance and distribution remain below historical levels. In a 1995 assessment of the species' status under the US Endangered Species Act, the US Fish and Wildlife Service concluded that a designation of threatened or endangered was warranted, but the species was "precluded from listing by higher listing priorities." A major revelation of the 1995 assessment was the recognition that information useful for determining population status was limited. Fundamental information was missing, including an accurate estimate of the species' distribution before European settlement and an estimate of the species' current distribution and trends. The objectives of this paper are to fill those gaps in knowledge. Historical records were compiled and, in combination with knowledge of the habitat requirements of the species, the historical range of the Swift Fox is estimated to be approximately 1.5 million km2. Using data collected between 2001 and 2006, the species' current distribution is estimated to be about 44% of its historical range in the United States and 3% in Canada. Under current land use, approximately 39% of the species' historical range contains grassland habitats with very good potential for Swift Fox occupation and another 10% supports grasslands with characteristics that are less preferred (e.g., a sparse shrub component or taller stature) but still suitable. Additionally, land use on at least 25% of the historical range supports dryland farming, which can be suitable for Swift Fox occupation. In the United States, approximately 52% of highest quality habitats currently available are occupied by Swift Foxes.

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Swift Fox, Vulpes velox, Den Use Patterns in Northwestern Texas

The Canadian Field-Naturalist ◽

10.22621/cfn.v121i1.396 ◽

2007 ◽

Vol 121 (1) ◽

pp. 71

Author(s):

Brady K. McGee ◽

Warren B. Ballard ◽

Kerry L. Nicholson

Keyword(s):

North America ◽

Predator Avoidance ◽

Canis Latrans ◽

Annual Number ◽

Vulpes Velox ◽

Swift Fox ◽

Use Patterns ◽

Den Use

Predator avoidance may be a reason why Swift Foxes (Vulpes velox) are one of the most burrow-dependent canids in North America. Typically Swift Foxes have multiple dens, which they frequently move among. As part of a larger study to reduce Coyote (Canis latrans) related mortalities on Swift Foxes, we installed artificial escape dens in areas occupied by Swift Foxes on Rita Blanca National Grassland, Dallam County, Texas. For this paper, our objective was to determine the effects of artificial escape dens on Swift Fox den use patterns. From January 2002 to August 2004 we captured, radio-collared, and monitored 55 Swift Foxes. We documented annual number of dens used, rate of den use (fidelity), distance between dens, den area, and den sharing. We compared treated (artificial dens installed) and untreated (no artificial dens) areas but found no differences in annual number of dens (P = 0.64; mean = 8), rate of den use (P = 0.96; mean = 35%), mean distance between dens (P = 0.99; mean = 2,311 m), den area (P = 0.55; mean = 5.72 km2), or den sharing (P = 0.46; mean = 42% of time). We did not observe an effect of artificial escape dens on Swift Fox den use patterns probably because artificial escape dens were designed for temporary escape cover rather than diurnal den use.

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